The present invention relates to electrical connectors, and more particularly to electrical connectors for protective conduit.
Modular electrical wiring systems have been developed to facilitate the electrical wiring of office landscaping systems. Typically, the modular electrical components include means for conveying current throughout the landscaping system, such as to lighting fixtures and plug receptacles, from a common power source. The landscaping system may be rapidly and readily wired in any one of a multitude of configurations, depending on how the modular electrical components are interconnected.
Typically, the modular electrical components include conduit segments, each comprising a flexible conduit having a connector housing at either end thereof. A plurality of wires are positioned within the conduit and connected at either end to terminal clips positioned within the opposite connector housings. When one of the connector housings is coupled to a mating electrical component, all of the terminal clips within the housing are connected to the mating component, and consequently, to wires within the conduit.
One well-known helical conduit connector housing is that made by Anderson Power Products of Worcester, Mass. This connector includes a clamping portion to which is secured a clamping member to entrap the conduit therebetween to secure the connector to the conduit. Examples of these connectors in landscaping systems are shown in U.S. Pat. No. 4,270,020, entitled PARTITION WIRING SYSTEM, issued May 26, 1981, to Kenworthy et al; and U.S. Pat. No. 4,135,775, entitled MOVABLE DIVIDER PANELS WITH ELECTRICAL WIRING, issued Jan. 23, 1979 to Driscoll. However, these connectors are time-consuming to install on the conduit because each of the connectors must be individually assembled by securing the clamping member and associated screws to the connector, and then each connector must be secured to the conduit. This assembly is labor-intensive, and results in conduit segments which are relatively expensive. Second, the clamps may become loosened during use or installation, such that the connector might become unattached from the conduit, exposing an uninsulated wire. Third, the clamping connection is relatively large and somewhat unsightly, rendering the connector excessively large to fit within some landscaping systems.
The conduit segments often include a ground terminal clip within the connector housing and electrically connected to the metal conduit to provide a system ground. The connector manufactured by Anderson Power Products includes a terminal clip and a ground wire extending from the terminal clip and fastened to the metal conduit under the clamping member used to secure the housing to the conduit. However, this construction is quite bulky and unsightly. Second, the mechanical connection is relatively large, rendering this connector unsuitable for many installations requiring relatively small connectors.
Another grounded connector includes a coil spring secured about the metal conduit and positioned under the housing secured to the conduit. The spring includes a portion extending into the connector housing which may be connected to a ground wire. An example of such a grounded connector may be seen in U.S. Pat. No. 4,205,888, entitled GROUND CONNECTOR FOR INTERLOCKED ARMOR ELECTRICAL CABLE, and issued June 3, 1980, to Wade. However, this connector requires a coil spring, which is a relatively expensive element excessively increasing the cost of the connector. Second, assembly of the connector is difficult because the spring must be wound about the conduit, such that the spring follows the helical groove on the conduit, prior to installing the housing.
Another wiring segment, manufactured by Amp Electric of Harrisburg, Pa., includes several insulated wires and a plug integrally molded onto the wire insulation. However, this wiring segment does not include protective conduit which should preferably be included to improve the strength and safety of the wiring segments. Second, these wiring segments cannot be used in many states where the electrical code requires conduit. This renders the wire segments virtually useless to a national manufacturer who must satisfy all state electrical codes. Third, these segments are difficult to properly ground because of the absence of a metal conduit.